How much did you save with cavity wall insulation?

r2015

Simple question


Who has had cavity wall insulation installed and how much are you saving on your heating bills?

penrhyn

Not a simple question.
To compare you would need identical heating patterns over a couple of years and a way of compensating for weather variability.

I used 25% less gas this year compared to last because we had a mild winter.

Smiley_Dan

One interesting topic to read up on in this area are "degree days".

As penryhn says, it depends. You'll see lots of n% quotes but it totally depends on your house and how much energy you will use (not have used).

Obviously people can quote year by year but that's not empirically sound to reach the conclusion you're seeking.

HappyMJ

Using the degree days as mentioned above which I log using the Imeasure site I saved about 5% on heating which equates to about 500kWh per year. The imeasure site gives you a baseline which is your hot water and cooking then the bit above the baseline is generally your heating. Hot water and cooking uses around 5,000kWh and heating uses about 10,000kWh...5% of 10,000kWh is 500kWh. Gas is charged at 4.2p/kWh so the annual savings are around £21. If I saved £145 as the energy trust say then my bill would have been very large to begin with. I'm paying £68 per month for gas and electricity. I was paying £75 per month a year ago but the weather was milder anyway.

I'm not quite sure how the energy trust got their figures. I have a fairly modern 20 year old 4 bed detached house, fully double glazed, 74-78% efficient boiler, house not heated at night or during weekdays, heated to 16 in morning and heated to 18 in late afternoon and 20 in evening, heated to 18 on weekend days.